body {
    padding: 0;
    margin: 0;
    height: 100vh;
    display: flex;
    justify-content: center;
    background-image: linear-gradient(#a18cd1 0%, #fbc2eb 100%);
    background-size: cover;
    flex: 1;
    align-items: center;
    /*取消竖线*/
    -webkit-user-select:none;/*谷歌 /Chrome*/
    -moz-user-select:none; /*火狐/Firefox*/
    -ms-user-select:none;    /*IE 10+*/
    user-select:none;
}
.login {
    text-align: center;
    margin: 0 auto;
    width: 600px;
    height: 520px;
    background-color: rgba(87, 86, 86, 0.2);
    border-radius: 25px;
    box-shadow: 5px 2px 35px -7px #ff9a9e;
}
.login h2 {
    margin-top: 40px;
    color: aliceblue;
    font-weight: 100;
}
.login_form {
    padding: 20px;
}
.login_form span {
    color: rgb(131, 220, 255);
    font-size: 18px;
    font-weight: 100;
}
.login_form input {
    background-color: transparent;
    width: 320px;
    padding: 2px;
    text-indent: 2px;
    color: white;
    font-size: 20px;
    height: 45px;
    margin: 30px 30px 30px 5px;
    outline: none;
    border: 0;
    border-bottom: 1px solid rgb(131, 220, 255);
}
input::placeholder {
    color: #fbc2eb;
    font-weight: 100;
    font-size: 18px;
    font-style: italic;
}
.login_btn {
    background-color: rgba(255, 255, 255, 0.582);
    border: 1px solid rgb(190, 225, 255);
    padding: 10px;
    width: 240px;
    height: 60px;
    border-radius: 30px;
    font-size: 30px;
    color: rgb(100, 183, 255);
    font-weight: 100;       
    margin-top: 5px;
}
.login_btn:hover {
    box-shadow: 2px 2px 15px 2px rgb(190, 225, 255);
    background-color: transparent;
    color: white;
    /* 选择动画 */
    animation: login_mation 0.5s;
}

    /* 定义动画 */
@keyframes login_mation
{
    from {
        background-color: rgba(255, 255, 255, 0.582);
        box-shadow: 0px 0px 15px 2px rgb(190, 225, 255);
    }
    to {
        background-color: transparent;
        color: white;
        box-shadow: 2px 2px 15px 2px rgb(190, 225, 255);
    }
}